The instant invention relates to wastewater treatment apparatus and more particularly to a trickle tower system employing a looped cord biomedia filter cartridge.
Increasingly strict wastewater regulations and growing population densities have fueled extensive research into the area of wastewater treatment, and in particular, biologically active wastewater treatment systems. A critical component of biologically active wastewater treatment systems are biological fixing materials, or biomedia, on which biological microorganisms can grow and digest wastes within wastewater. The typical biomedia types currently in use include stones, ceramic pellets, wood chips, plastic strips, plastic tubes, packed sand and looped cord biomedia having a braided or knit backbone and a plurality of fibers or loops that radiate outwardly from the backbone. Although various types of biomedia are being used in different treatment facilities, there is still significant research being conducted on implementation of the biomedia to achieve the most efficient wastewater treatment. Efficient operation of the biomedia in waste digestion requires good circulation of both water and oxygen, extended contact of the wastewater with the biomedia and the ability to clear digested wastes. Accordingly, biomedia systems must provide means for circulating and aerating the wastewater to provide oxygen, or other select gases for the microorganisms to function in an efficient manner.
While existing applications of biomedia have been effective, and have been well received in the industry, there is nevertheless a continuing need for research and development of newer, smaller, more efficient systems for treating wastewater, and in particular there is a great need for new and improved biomedia filter assemblies for use in these systems.
In this regard, the instant invention provides a highly compact and highly efficient trickle tower filter assembly employing an improved looped cord biomedia filter cartridge. The trickle tower includes a base tank that holds a volume of wastewater to be processed. The biomedia filter cartridge is mounted on top of the base tank and comprises a cylindrical frame having a plurality of upper and lower horizontally extending, concentric hanger rings. The biomedia filter cartridge further comprises a looped cord biomedia that is interlaced, under tension, between the upper and lower hanger rings to create a plurality of parallel vertically extending, linear lengths of looped cord biomedia. The concentric hanger rings are equally radially spaced, and include equally circumferentially spaced notches for interlacing the looped cord biomedia. The looped cord biomedia provides a large amount of surface area in a small area and is thus an ideal fixing media for trapping highly dense populations of waste-digesting microorganisms. Tensioning the vertically extending lengths of looped cord media creates a highly desirably laminar downward flow of wastewater over the surfaces of the looped cord biomedia. Laminar flow maintains the water in uniform contact with the biomedia and exposes the water to prolonged contact with the biomedia, thereby achieving an improved biological filtration. Water is evenly distributed over the top of the filter cartridge by a rotatable spray bar assembly mounted on top of the filter cartridge. A pump connected between the base tank and the spray bar continuously circulates wastewater from the base tank to the spray bar. As the spray bar rotates it provide a uniform spray of wastewater over the top of the filter cartridge, the wastewater then trickling down the vertical lengths of looped cord biomedia in a laminar flow. During the downward flow, the wastewater comes into contact with the biologically active microorganisms on the biomedia and eventually trickles back into the base tank for re-circulation. The base tank, filter cartridge and spray bar elements are each constructed as a separate module to allow for expansion and the use of multiple stacked filter cartridges. Each module is surrounded by a side wall that essentially creates a self-contained environment that can be enriched with oxygen, or other select gases introduced into the wastewater.
Accordingly, among the objects of the instant invention are: the provision of a wastewater treatment apparatus that is compact and highly efficient at reducing nutrient compounds, such as BOD.sub.5 /COD, ammonia, and phosphor levels in wastewater; the provision of a trickle tower filter apparatus employing a vertically tensioned biomedia that promotes laminar flow of wastewater over the biomedia; the provision of a biomedia filter cartridge containing concentric hanger rings that equally space the biomedia, and hold the biomedia under tension; the provision of a trickle tower assembly that is modular and expandable for growing wastewater treatment needs; and the provision of a trickle tower apparatus that creates a substantially self-contained environment that can be enriched with pure oxygen, or other select gases.
Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.